US2626670A - Propeller control - Google Patents

Description

Jan. 27, 1953 R. E. MOORE PROPELLER CONTROL 4 sheets-sheet 2 Filed Oct. 8, 1945 INVENTOR RICHARD E. Mamas E N m w A m y Jan. 27,1953 R. E. MOORE 2,626,670

PROPELLER con'mor.

Filed Oct. 8, 1945 4 Sheets-Sheet 5 Q Z10 INVENTOR Z5 9 RmHARuEMuuRE A 7 Ms ATTORNEYS Jan. 27,1953 R. E. MOORE 2,626,610

PROPELLER CONTROL Filed Oct. 8, 1945 4 Sheets-Sheet 4 INVENTOR RICHARD E. Muum:

I ///s ATTORNEYS Patented Jan. 27, 1953 UNITED? STATES ATENT oFFicE.

itieiia'mn. Moore, Dayton, Ohio, assi'gno'r ween eral Mot rs Corporation, Detroit; Mich acor poration of-Delaware Application data 8, 1945; sea-1st. 6521136 1 22 Claims. (01. 170-46021) This invention relates to controllable pitch propellers for aircraft: thatare automatically responsive to changes in speed for shifting the. blade inclination to make for best efliciencyof engine operation. I p g p The principal objector the invention-is'to prevent overspeeding of the propeller when a change in speed of the prime mover occurs; 7

Propellersthat haveibl'ades withhigh built-in forces tending t9 shift the blade to decrease pitch require a highincrea'se-pitch application of force to hold the blades at the required angle during normal governed operation. If that force is suddenly released, it is easily conceivable that the blades will immediately begin to decrease pitch. If the force operating to; hold the blades at the required angle is that of; afiuid medium under pressure, then the ratewo-f the decrease of blade angle will be controlled by the restriction to flow of the pressure fluidfromthe blade shifting unit in accordance with the tendency for the blade to seek the decrease pitch position.

It is therefore'anobject of this inventionv to prevent overspeeding of'a controllable pitch propeller by restricting;- the rate of-chan'ge in decrease-pitch movement of." tlie'bl-ad'es;

Another object of the invention is to provide a system of control for" variable pitch propellers that affords a normal operating forc'erforassisting the blade movement to decrease pitch, and a higher operating force for: holding the blade movement against: tendency to move to decrease pitch and for shifting: the. bla'd'eeto"increasepitch, with restricting means for limitingthe maximum rate of change.

Still another'object ofv the invention is to provide a valve and linkage articulation in which-an angle slot lever producesxadequat'e damping to prevent the erratic and reversing flow forces to start the governor valve chattering thereby causing unstable control. v

These and other: objects of the invention. are accomplished by 'providinga'high capacity pressure source for operatingrthe blade torque-units through the selective con'trolrby agovemor'mechanism, the potential of. thepress'ure delivered to the governor mechanismbei'ng variably controlled so that it is raised to a: higher value onmov'e ment of the governonmechanism to demand more force, and, introducing controlled resistance-to movement of the governor me'chanism, with restricted drain back of fluid pressure fromthe blade torque-units when the governor mechanism is distributingthe fiuidpress-ure to -the decrease pitch side 'of the-'torque u'm' t;

Further objects; andadvantages of the present invention will b'e apparent from the following description reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings: I

Fig. 1 is a schematic view of a control system for variable pitch propellers involving the instant invention. K r r 7 v V I Fig. la is a diagrammatic View of the invention, illustrating the ports in simplified circuit connection.

Fig.2 is a. diagrammatic detail illustrating the relationof the parts of the governor mechanism when distributing: force for decrease of pitch.

Fig. 3 is a similar viewillustrating the relation of the parts when distributing force for increase fpitch.

Fig. 4" is a mid-sectional view through the governor mechanism substantially as indicated by the line and arrows 4-4 of Fig. 5'.

Fig. ,5'is an elevational view) or the governor mechanism, substantially as indicated by the arrow 55 in Figs. 4 and 12.

Fig. 6 is a top plan: view or the governor mechanism substantially as indicated by the arrows 6 inFigs. 4 and 12.:

Fig. '7 is an elevational view of the supporting plate of. the governormechanism substantially as indicated by the line and. arrows 'l'-1 of Fi 6.

Fig, 8 is a transverse sectional view there'- through substantially. as indicated by the line and: arrows 8 'i-l of Fig. 7.

Figs. 9; l0 and 11 are, fragmentary sectional views showing the. porting arrangement of the governor valve. mechanism substantially as indicated by the lines and arrows 9-9,- Ill-It, and l I -ll respectively of Fig. 7.

Fig. 12 is'a' structural view with the governor mechanism shown in elevation, and making application of the invention'illustrated in the foregoing figures.

Referring specifically to the drawing, and first with resp'e'ctitd Fig. 1d, l ll refers' to'a single blade of a propeller mechanism that is mounted in asocket of a hub for: pitch shifting movernen-tby meansof atorqu-unit li'. Here the torq ue unit comprises a cylinder I and piston l 6. the latter of which isprfo-vided with: a-rod I8 ending in a rack 20"int'erengagin "ith aqg'ear 22 fast to or driving-the bladell its pitch shifting movements; Theblade is so constructed that it has a tendency to shift'towajrdthedecrease pitch position'" asind'i'c'ated' by the arrow"! when the ropell'er' is" rotated" in tlie direction of" the arrow 25 3 about the propeller shift axis 27-29, which tendency may be by reason of the center of pressure, or the center of mass of the blade being located between the axis of pitch rotation 28 and the trailing edge 30 of the blade.

The torque unit is operated by application of fluid under pressure to either side of the piston [6, such as the chamber 32 and passage 3 3 for increase pitch shift, or the chamber 36 and passage 38 for decrease pitch shift. The application of fluid pressure to one side or the other of the torque unit is determined by the action of a governor mechanism 40 that provides a porting sleeve 42 with control ports 44 and 46 leading to the passages 34 and 38 respectively, and a pressure source port 43. A valve plunger E3 slidable along the sleeve has control port lands 52 and 54 adapted in the on-speed position to substantially cover the control ports 44 and d6 respectively. The on-speed position is determined by the balance of opposing forces acting on the valve plunger 50, including centrifugal force acting upon the member 50 tending to move it in one direction along the sleeve 42, and an opposing force of a spring 56 acting upon a lever 58 articulated at 68 to an extension [52 of the plunger, the opposite end of the lever ES'resting on a fulcrum 64.

A fluid medium under variable pressure is supplied to the governor mechanism through the port 48 by a passage 66 that connects with the outlet of a high capacity pump (38, the potential of the pressure being controlled by a pressure control valve it that secures a pressure of normal or relatively low value always available at the port 43 for maintaining the system completely filled with fluid, and for operating low force required units, and immediately steps up the potential of the pressure to meet the requirements for operating higher force required units. The pressure control unit provides a chamber E2 inserted in the passage 66 and thereby always subject to the potential of the pressure from the pump 68, and houses a plunger l4 spring-urged by T6 to one end of the chamber 12 in which position a land 78 of the plunger M completely covers a relief or blow-off port 88', which when open reduces the pressure in the chamber i2 and passage 66.

The potential of pressure in the passage 66 and chamber I2 at the instant of relief or blow-off through port 80 is determined by the resultant of forces acting upon the plunger M, and includes centrifugal force and the. urge of spring 1'5 acting to thrust the plunger 74 outwardly to close the port 80, and opposed by the pressure of the fluid within the chamber 12 acting against the annular face 82 of the land 78 and against the top surface of head .92. of piston 14 (by way of apertures 94) to move the plunger inward to open the port 8!). In Fig. la, centrifugal force acts upon both the valve member 50 of the governor mechanism and the plunger 74 of the pressure control valve, to move them outward which is toward the top of the sheet. From this it will be seen that the pressure control valve it acts to variably limit the low stage of pressure in the system in accordance with the speed of rotation, for which reason the limit of pressure in the system for a propeller that is rotating at a slow speed will be a little lower than the limit of pressure in the system for the same propeller rotating at a faster speed. The pressure so limited is suitable for distribution by the governor mechanism and may be sufiicient to maintain the blades at the required angle during normal governed cperation, and is sufiicient for assisting the blades in their movement toward decrease pitch. A greater pressure potential is required or desired to make a quick shift in the increase-pitch direction, for which reason means are incorporated for automatically increasing that potential when the work to be done by the torque-units is increased.

An extension of the control valve plunger 14 provides a small piston face 84 confined in a chamber 35 which has a fluid connection by way of the passage 88 with the increase-pitch port 44 of the governor mechanism. Thus, when the governor valve member 50 moves to a position to distribute fluid under pressure to the pitch-increase port 44, the potential of that pressure will also be applied to the passage 88, chamber 86 and against the piston face 84 to assist centrifugal force and spring force on plunger M in keeping the port closed. The potential of the pressure in the passage 66 and bore of the porting sleeve 42 and control port 44 is therefore suddenly increased to fill the needs of the work to be done by the torque-unit connected with port st. To insure that the pressure control valve 10 will promptly respond to the variable forces that may be applied to it, the back side of the land 18 is relieved by a passage 90, and the plunger '12 is provided with a dash-pot head 92 that is relieved by passages 94 therethrough.

Further control of the forces applied to the torque unit are embodied in the construction of the governor mechanism and include means for restricting the drain of fluid from the torque unit, and a controlled resistance to movement of the valve member when it shifts from one position to another. The last is incorporated in the articulation 68 between the lever 58 and the extension 62 of the member 50. The extension 62 is slotted at 95 to receive one end of the lever 58 which is provided with a slot 98 at an incline to its length as shown and straddles a pin I00 extending across the slot 96 of the extension 62. That articulation is such that spring force exerted on the lever is applied substantially as indicated by the arrow L, but the inclination of the slot 98 introduces such component as indicated by the arrow S, with the result that there is a tendency to move the valve member 58 laterally in the direction of the arrow C as indicated. That lateral component of force on the valve member 50 tends to cook it against one side of the bore of the sleeve 42 as indicated at Hi2, and slightly increases the resistance to movement or produces damping to chattering of the valve.

Limiting the rate of decrease-pitch change is also controlled by restricting the drain from the increase-pitch side of the torque unit, and is accomplished by extending the valve member 50 outwardly at [fi l beyond theincrease pitch land 52 and drilling it out at I06 to extend beneath an additional land I08 and an annular groove I [0 between the lands 52 and H38. Small passages 1 l2 are then drilled to connect the groove I I0 and drilling Hi6. Figs. 2 and 3 illustrate the relation of the parts in eifecting the limiting control of the pitch shifting movement, Fig. 2 designating a distribution of pressure fluid to the torque-unit for decreasing the pitch, and Fig. 3 designating a distribution of the pressure fluid to the torqueunit for increasing the pitch. In both instances as also in Fig. l, the valve member 501s subjected to the opposing forces of the spring 56 through the lever 58 and centrifugal force, one or the other dominating according to the position of the valve member, but the spring force always being present, the lateral cocking of the member 50 to ace-6 67c he ide if llfii bore rine-s. l' g' .2: sewers present. Whenthe-valve member-is distributing be great enoughto cause a;-- sudden 7 or too great a shift; anddsherein ,controlled by the additional la-ndj- I 08 and therestricted drain'holes- II 2 In this shifted position of-the valvememberin the channel II 0' '-iso-pen to thecontrol portgfl so-that drain from the torque '-u'nit= ther'ethrough rnust flow through the--restrictions- I I-2i The-small arrows indicate thepath off th fiuid pressureifiowing through the governor-mechanism When thevalve memb'eris distributingthe fluidpressure -to the increase-pitch 'port"44 -asindicated iii-Fig; 3; then-ports -48: and 44' are communication; so-- that fluid-under--pressureis delivered to the chamber -32" ofthe; torque-unit in opposition to thetendency of the blade toshift; thereby effecting a-;shi-ft-* by -the torque-unit to an increase-pitch position; Return from" or drain from-the torque unit' is-through the passage 38 and control port 46. At the same time that-distribution is being mad'e tothe port 44; the passage 8a is also subjected to thepressurefrom port 48' through. whichit-exertsitselfon the small piston facefit of the-pressure cont-rol'valve to step up the-potentialof the pressure in passage 65; There is then available a-grea-ter pressure-force for: the torque-unit function-that is doing the greater-part0?the work,that is, a greater-force is directed to the torquemnitforeffecting shift in apitch-iricreasesense;and the rateof shift of the blade by tlie torque-un it fordecrease of pitch itvlimited by therestricted port-of itsdrain; The tendency- M the valve to hunt and vibrate 'during' any; distributing movement is reducedE-bythelateral cocking or the distributing--valve-in"its porting sleeve. 7 i

Ail-structural application ofthe features of" the inventionadopted in a propellermechanism are shownin Figs. a tar-l2 inch-isive;Where Figs.- 4to "1-1 relate .to a governor mechanis-m and Fig; '12-il1us-" trates itsmountir igand inclusion of a hydrauli-c regulator. for an aircraft propeller." With that in mind, consider that I20-refers=to apropel-ler'shaft thatflextends from androtates -withrespect to-an engine. nosing or= gear "casing;- and has driving relationrthrough splines I-2-2-fwith a propeller hub I24 ithatflprovides a--=plurality*ofsockets I26 'in whichtth'e blades aremounted for-pitch shifting movement. The hub has an extension I2-8-on Wllifihi is Jnounted a regulator I30 -=contai-ninga quantity: of; operatingfluidand control mechanism; such. as the pump: 68'; the-pressure control valve. 10, the. governormechan-ism 40,-" allhydraulically. connected by passages, such as I 32 so thatfluid contained within the-enclosure I 34 of the tregulatpr may be drawn: therefrom anddelivered under.- pressure to thetorque=unitswithin the sockets. Theregulatorembodiesaplate I36 enclosingseveral of the passages; I32 that, end withappropriatepads I 38;t0rwhiqhisrsecuredgthe lemen s. .ott e c ntr epper tu h re h n to be e o ernor. me haui mil. t e r sp c v n ts and na ls having OQI BITa iHgLaIldYCOmP menta'rily positioned ports: jo'r' .bpd tliil fih suchthat the fluid I circuit is properly made upon clamping 6-. he; lemen o n r im h ismnrn aeer 110 1 e' ilete I361 A cover member pleting the enclosure' l34; the, assembly having ajournal bearing at I44 and I 46% with the; plate I 3 B and cover I40; along withlifteofi fiuid seals I4-8-- and; I50; The; assembly is-"restrain'ed against'rotation with the-propellerby a-partIST-anchoredto they engine structure, and provides a control ring I54 operatedby control sha-fts I56 from-an osciliatable ringgear l 58 for selecting the speed settingat' which-the propeller-is tooperate; Link'- age or cables from theicockpit connect with; the lever I60, and may effect the axial; movement; of the control ring: I545 along theadapter assembly so as to actuatea' carriage I62'that'supports the fulcrum 64"that is engagedby the lever :58 offthe governor mechanisrrn Referring tmFig; la; as the fulcrum is moved closer to or'further from the 'point of spring pressurevupon" the lever; the relation of opposing; forces applied" to the"lever and valve are altered andjadifferentjspeed is'selected at which the balance of forceswill ensue. A schematic arrangement jof this structure as ap plied a pr p ller. ofi h ype; sclo ed; n

Blanchard et a1, 2,307,101,, is shown in; Fig. 1,.

hereof.

For specific descriptionyofthe; governor structure, reference is now-made to Figs. etoilinclusive, where I64'refers toaplatehaving a rib'or boss I66'extending from on e side thereof; and designed tonest'in asocketor welli I68 of the plate I36 andagainst, the pad, I3 8 ',aswill}be P iesently explained. Theb'oss I66 isdrilled' out at I10 to receive thetporting sleeve,42in,a ,press,fit relation as shown in Fig. ,4,, where the sleeve .provides annular exterior grooves I12, I14F'andj I161 into which the control ports .44. 46iand the pressure port 48 opens respectively. The opposite side of theplate I64 is grooved asi-showniin Fig. 7, such as at I18, ,Ivand I82, andthrough holes are drilled to connect those grooves with the bore I10at the properpoint to registerwith the annular grooves of theflportingmsleeve 42; Thus, at one end of the groove I18itliereisahole I84. connectingwith the boreri 10 'atsuchlocation. as to connect or register, withgroove. I121 of the sleeve 42,,whi1e-.a ,ho1e IBS/imone endJofiI80 registers forconnection with thegroove/IH', and hole I88 in one end of I82connectswith groove I16. It will. be, observedJthat, all of the, grooves I13 to I82 extend fromthe proximity of .the central part of the plate wherethey each connect with the bore I10 toaflpointov eer the thinner part or flange of thevplate whereeach is provided in the opposite end with holes I90, I92 and. L84 respectively as shown ineFigs. 9, lO'and 11. A cover plate I96 is then securedtothe face of the plate I64 '50 as tocoverall' of'the passages formed by the grooves and holes; Machining or grooving as at I98 makes for-:compact arrange ment of spring 56 that restsupon an" adjustable seat, 200 carried'b'y ascrew stud 202 supported ina plate 204 located ina notch 2050f the edge of plate-I64 at one1end' of the boreI 10; The plate 2&4 is attached by a screw device208threaded, into the body of the plate I64, and ends in a depending lug ortongue-2I-0 engaging a notch of the seat 200, which preventsth e seat turning when the screwstud is turned-over ratchetmeans 2I2 holding it in place; Depressing thescrew stud 202 will displace the ratchet means and permit rotation-ofthe stud relativeto' the seat 200 for adjustment ofthe spring 56'.

I40 secured to the plate I36: cooperates; withian adapter assembly l 42 for coma Ihe other end of the spring 56 engages a seat or pad 2I4 fixed to an intermediate part of the lever 58 where there is also secured the middle leg 2I5 of a flat leaf spring member 2I6 of M-shape, the end legs 2I8 ofwhich are secured to studs or posts 228 mounted on the face of the plates I64 and I96. These posts are secured in holes 222 at the lower edge of the plates and have cross apertures to receive screw devices 224 that pass through lugs 225 of way pieces 228 and the ends of legs 2II on the spring 2I6 to clamp them in place. The way-pieces are of sufficient length to-pass across the bottom edge of the assembled plates. I64 and I96 to engage locating notches 230 by which the ways are kept rigidly in parallelism and perpendicular to plates. The ways are of channel section as shown in Fig. 5 and are adapted to freely guide the rolling motion of the carriage I62 in its movement along the length of the lever 58. The carriage is mounted on two pairs of rollers 232 within the channel of the Ways 228 and supports the fulcrum roller 64 on the same shaft 234, while the second shaft 236 supports a roller stop 238 for the valve member in it slow pitch position. web of the ways cooperate with a cross pin 242 on the carriage to determine the extent of travel that the carriage can encounter along the ways and consequently along the lever 58.

This governor mechanism is adapted for mounting on the plate I36 since the rear side of the plate I64 is machined flat at 255 to closely engage the machine surface 252 of the plate I35, and so that the holes. I99 to I94 register with appropriate openings to the passages I32 for completion of the fluid circuit shown in Fig. 1. Holddown devices, such as screws 254 pass through apertures 256 in the plate I64 to securely hold the unit in place, the rib portion I66 nesting in the well I68 of the plate. When so mounted, the basic speed at which the governor unit is to control may be selected from the cockpit which acts through the lever I 6! the control shafts I58 and the carriage I62 to move the fulcrum 64 along, the lever 58. The speed having been selected by positioning the fulcrum, rotation of the propeller carries with it the governor mechanism, in which the valve member 52 responding to the action of centrifugal force and opposing spring force assumes an equilibrium or on-speed position in which the lands 52 and 54 cover both control ports 44 and 45. Should an off-speed condition arise, the member 55 moves along the bore of the porting sleeve to properly open the ports for distribution of pressure fluid to the torque-unit in correcting for the off-speed, as has been hereinbefore described.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. In a system of control for variable load devices having tendencies to shift to a lesser load condition, the combination comprising, a double acting torque unit for adjusting the device in both increase and decrease load directions, a single source of torque-unit-operating-force, a governor having a centrifugally operated and yieldingly opposed member for selectively distributing the operating force to one side or the other of the torque-unit in order to obtain load increase and load decrease, said member including means operable, when said governor is distribut- Slots 240 in the 8 ing force to assist the device in its tendency to shift to said one end of the load range, to retard that tendency of the device to shift.

2. In a system of control for variable load devices having tendencies to shift to a lesser load condition, the combination comprising, a double acting'torque unit for adjusting the device in both increase and decrease load directions, a source of power providing a surplus of torqueunit-operating force, means for controlling the operating force to a predetermined potential by selecting a portion of the source of power for application to the torque-unit and including means for increasing the potential of the operating force to a value above th predetermined value in response to increased demands of the torque-unit by selecting a greater portion of the source of power, a governor having a centrifugally operated and yieldingly opposed member for selectively distributing the operating force to the torque-unit to effect load increase and load decrease in response to speed change, said governor being operable when distributing operating force to assist the tendency of the device to shift for retarding that tendency of the device to shift, and having means operable, when distributing operating force to oppose the tendency of said device to shift, to efiect operation of the force controlling means for increasing the potential value.

3. In a system of control for variable load devices having tendencies to shift to a lesser load condition, the combination comprising, a double acting torque unit for adjusting the device in both increase and decrease load directions, a surplus source of torque-unit-operating-force, means separating the surplus for limiting the operating force to a value suitable to effect movement of the torque-unit in accordance with the work to be done by it, and including a normally low value for assisting the tendency of the device movement, and a variable higher value for opposing the tendency of device .movement, a governor having a centrifugally operated and yieldingly opposed member for selectively distributing the operating force after thesurplus has been separated and thus limited to the torqueunit in order to obtain device movement in accordance with speed variation, said member including means for restricting the rate of movement of the torque-unit when the member is shifted to distribute the operating force in assistance of the device tendency.

4. In asystem of control for variable load devices having tendencies toshift to a lesser load condition, the combination comprising, a double acting torque unit for adjusting the device in both increase and decrease load directions, a source of torque-unit-operating-force, means for limiting the operating force to a value suitable to effect movement of the torque-unit in accordance with the work to be done by it, and including a normally low value for assisting the tendency of device movement, and a variable higher value for opposing the tendency of device movement, a governor having a spring and a member for selectively distributing the operating force to the torque-unit in order to obtain load change in accordance with speed variation, said member being under joint control by two normally opposed forces, one force being the force of the spring and the other being centrifugal force acting upon said member, means articulated to the member for transmitting the force of the spring to the member, means including said articulation for introducing a slight lateral thrust to said member for damping its movement by the centrifugal or spring force, and means included in said member for restricting the operation of said torque-unit when said member is shifted to distribute the operating force in assistance to the tendency of the device to shift.

5. In a system of control for variable load devices having tendencies to shift to a lesser load condition, the combination comprising, a double acting torque unit for adjusting the device in both. increase and decrease load directions, a source of fluid under pressure providing a surplus of pressure for operating the torque-units, a gOV- ernor having a. valve member centrifugally operated and yieldingly opposed for selectively distributing the fluid pressure to the torque-unit in order to obtain load change in accordance with speed change, means operable when said valve member distributes fluid pressure to assist the device tendency, to then restrict operation of the torque-unit.

6. In a system. of control for variable load devices having tendencies to shift to a lesser load condition, the combination comprising, a double acting torque unit for adjusting the device in both increase anddecrease load directions, a source of surplus fluid under pressure for operating the torque-units, a governor having a valve member centrifugally operated and yieldingly opposed for selectively distributing the fluid pressure to the torque-unit in order to obtain a load change in accordance with speed change, means so controlling the fluid pressuredelivered to the governor by diverting a substantial surplus of the pressure source that a normal low pressure will be available at all times, and by diverting a lesser surplus that a variable increased pressure will be available when the valve member directs the fluid pressure to the torque-unit for opposing the tendency of device movement, and means operable when said valve member distributes said normal pressure to the torque-unit assisting the tendency of device movement for restricting the movement of said torque-unit.

7. In a system of control for variable load devices having tendencies to shift to a lesser load condition, the combination comprising, a double acting torque unit for adjusting the device in both increase and decrease load directions, a source of surplus fluid under pressure for operating the torque-units, a governor mechanism for distributing a part of the fluid under pressure to the torque-unit in order to obtain a load change in accordance with speed change, said mechanism including control ports. with connections to the torque-unit, and a valve member with lands normally covering said controlv ports when. the valve is in the on-speed position, and means operable when the governor mechanism is distributing fluid pressure to the torque unit to assist the device tendency, for restricting the operation of the torque-unit by altering the escape of surplus fluid under pressure.

8. The combination set forth in claim '7, wherein the means for restricting operation of the torque-unit include means for retarding the drain of pressure fluid from the torque-unit.

9-, The. combination set forth in claim 7, wherein the-restricting means comprisesan additional land on the. valve member and a. restricted passage operable to. connect with one of the control port's when the: valve member is shifted in one 10; direction from the on-speed positioning, whereby the drain of pressure fluid from the torque-unit through that control port is delayed.

10. In a system of control for variable load devices having tendencies to. shift to a lesser load condition, the combination comprising, a double acting torque unit for adjusting the device in both increase and decrease load directions, a fluid pressure source providing a surplus over an essential potential for operating the torque-units, a governor for distributing the pressure source to either chamber of the torque-unit in order to obtain load shift in accordance with change of speed, said governor comprising a body with a pair of control ports each leading to one chamber of the torque unit, and a valve member normally covering the control ports when in the onspeed position and operable under joint control of two normally opposed forces for opening either control port to the pressure source, one force being the force of aspring that tends to move the valve to a position for decrease load and the other force being centrifugal force that tends to move the valve to a position for increase load, means coupled with the valve member for transmitting the spring force thereto and for resisting movement of the valve member, pressure control means for limiting the pressure source to a normal value by diverting all of the surplus from the governor when the governor distributes the pressure to the load decrease port in assistance of the tendency of device movement, and for variably increasing the pressure to a higher value by diverting only a part of the surplus from the governor when the governor distributes the pressure to the increase load control port in opposition to the tendency of device movement, and means including a part of the valve member adapted to cooperate with the increase-load control port when the valve member is distributing pressure fluid for decrease load change, to control the rate of decrease load change.

11. The combination set forth in claim 10, in which the means for coupling the spring force with the valve member for resisting movement of the valve member includes a lever pivoted to the valve member by a pinand slot provisions, the slot being provided by the lever and inclined with respect to the valve member so as to earn the valve member laterally with respect to its path of movement, whereby the valve member is so cocked as to deprive it of its freedom of movement.

12. The combination set forth in claim 10, in which the part of the valve member adapted to cooperate with the increase-load control port for controlling the rate of load change comprises a hollowed extension of the valve member, and an additional land axially spaced. from the land adapted to cover the increase-load control port, with small apertures connecting from between those lands to the hollow of the valve member, such that shift of the valve member to effect drain of pressure fluid from the torque-unit through the increase-load port is thereby restricted.

13. In a system of control for variable load devices requiring a substantially greater force application to shift for increase load setting than is needed to shift for decrease load setting, com p s i bination, a double acting torque motor having separate chambers for effecting increase and decrease load e, a. n le fluid pressure pump whose output provides a surplus pressure component over the essential pressure components required to effect either of the load settings, a variable pressure control valve for separating the surplus component from the essential component required to effect a decrease load shift, and for separating a different surplus component from a different essential component required to efiect an increase load shift, a governor valve always exposed to the essential component for applying the essential component to one or the other of the torque unit chambers, and means operable when the governor applies the essential component to the torque unit chamber for load increase setting for assisting the variable pressure valve in reducing the surplus component, and means brought into operation when the governor valve applies an essential component to the torque unit chamber for decreasing the setting for restricting the rate of decrease load setting.

14. A governor for fluid pressure, comprising in combination, a support plate having interior channels one end of which opens to one face of the plate, a medial boss extending across the plate and having a bore parallel with the face of the plate, passages connecting each of the channels with the said bore at spaced points throughout its length, a porting sleeve located in the bore and having ports opening from its bore to the ends of the passages opening into the plate bore, a valve plunger shiftably supported within the bore of the porting sleeve and having a pair of spaced lands adapted normally to cover the end ports of said porting sleeve, a pair of brackets extending from the plate, one of said brackets supporting a movable carriage, a lever having one end resting on the carriage and the other end connected to an end of the valve plunger, and yielding means disposed between the lever and the other bracket to urge the lever to engage the carriage, said valve plunger being adapted to move along the bore of the porting sleeve to uncover either of the normally covered ports, a third land situated on the valve plunger near one of the first mentioned lands, and a restricted passage opening from between the said lands to the outside of the valve plunger.

15. The combination set forth in claim 14 wherein the lever connected to the end of the valve plunger embraces a cross pin in the end of the valve plunger and a slot in the end of the lever, said slot being at a slight angle to the length of the lever so that spring pressure against the lever cams the valve plunger against one side of the porting sleeve.

16. A governor for fluid pressure, comprising in combination, a body member providing a cylindrical bore, fluid passages providing a middle and two spaced openings along the length of said bore, a porting sleeve located in the bore and providing ports each of which communicate with one of said openings, a cylindrical valve plunger shiftably supported within the porting sleeve, a pair of spaced lands on the valve plunger adapted to cover the end ports of said sleeve, and a third land on the valve plunger and spaced from one of said pair of lands, an axial bore in one end of said valve plunger, and a cross bore connecting said axial bore with the space between the third land and the adjacent end land.

17. In a fluid pressure system having a high capacity pump and a governor valve for applying pressures of different potential to each of two control ports, the combination comprising, a valve'plunger having a pair of spaced lands normally covering the two control ports and adap upon change of position to uncover one or the other of said control ports and connect it with a pressure supply line, an additional land on the plunger outward of one of the pair of control lands, a restricted passage opening outward of said one paired land by-passing the additional land so that shifting of the valve plunger to connect the other control port with the pressure supply line will effect retarded drain from the adjacent control port, a variable pressure control valve between the pump and the supply line to the valve plunger for supplying a relatively low essential pressure potential to one of the: control ports when the valve plunger connects it with the supply line, and fluid connections from the other control port to the variable pressure control valve for increasing the essential pressure potential in the supply line when the valve plunger connects the said other control port with the pressure supply line.

18. In a fluid pressure system having a high: capacity pump and a governor valve for applying pressures of different potential to each of two control ports, the combination comprising, a shiftable valve plunger exposed to a pressure supply line from the pump and having a pair of spaced lands covering the control ports, a variable pressure control valve between the pump output and the pressure supply line for limiting the potential of pressure in the pressure supply line to that essential for application to either of the control ports, and fluid connections be tween the control port requiring the higher pressure application and the variable pressure con-- trol valve for assisting the said pressure control valve in increasing the essential pressure potential in the supply line when the valve plunger shifts to connect the control port requiring the higher pressure application to the pressure supply line, said valve plunger having a restricted passage connectible with the control port requiring the higher pressure application to dampen drain therefrom when the valve plunger shifts to connect the other control port with the pressure supply line.

19. A fluid pressure mechanism for controlling the rate of pitch change in a variable pitch aircraft propeller, comprising reversible acting pitch changing fluid pressure motors, a regulator rotatable with the propeller and including a fluid pressure source, a governor valve unit carried by the regulator and having a pair of control ports for distributing the fluid pressure to either side of the pitch changing motors in response to change in speed of regulator rotation for maintaining a substantially constant propeller speed, means in said unit for delaying the distribution to said control ports including a porting sleeve, a valve plunger, and a spring pressed lever articulated with the plunger, said articulation comprising a pivot pin carried by the valve plunger, and a slot in the lever disposed at an angle to the perpendicular of plunger movement so as to impart a camming action of the plunger against the side of the porting sleeve, and orifice means in said unit for limiting the rate of flow of fluid pressure from one of the control ports when the governor valve is distributing fluid pressure to the other control port.

20. A fluid pressure mechanism for controlling the rate of pitch change in a variable'pitch aircraft propeller, comprising reversible acting pitch changing fluid pressure motors, a regulator rotatable with the propeller and including a fluid 13 pressure source, a governor valve unit carried by the regulator and having a pair of control ports for distributing the fluid pressure to either side of the pitch changing motors in response to change in speed of regulator rotation for maintaining a substantially constant propeller speed, said governor valve unit comprising a plate channeled for fluid passage to and from the control ports, said plate having a hollow boss radially disposed on a conduit support carried by the regulator for connecting the channels with conduits, a spring and a valve plunger urged thereby movable along the hollow of the boss for selectively connecting the channels, and a restricted aperture in the valve plunger adapted to register with one of the channels from which fluid is flowing upon predetermined movement of the valve plunger to distribute fluid to the channel tending to decrease propeller pitch whereby the rate of fluid flow from one of the control ports is limited when the governor valve is distributing fluid pressure to the other control port, and means in said unit for delaying the distribution to said control ports.

21. A fluid pressure mechanism for controlling the rate of pitch change in a variable pitch aircraft propeller, comprising reversible acting pitch changing fluid pressure motors, a regulator rotatable with the propeller and including a fluid pressure source, a governor valve unit carried by the regulator and having a pair of control ports for distributing the fluid pressure to either side of the pitch changing motors in response to change in speed of regulator rotation for maintaining a substantially constant propeller speed, said governor valve unit comprising a radially disposed bore with ports leading to the pressure source and the control ports, a valve plunger slidable in and out of the bore in response to domination of spring force or opposed centrifugal force and adapted in the on-speed condition to govern the control ports, a lever for transmitting the spring force to the valve member and having connection therewith through a camming means for inducing cock of the plunger against one side of the bore to reduce its freedom of in- Ward and outward movement, an additional land on the valve plunger in close proximity to a land of one of the control ports adapted to approach said one control port when the valve plunger moves in one direction, and a restricted opening in the valve plunger extending from between the proximate lands to reduce the rate of flow through one said control port from said fluid pressure motors when the valve member has moved in said one direction to distribute flow tending to decrease propeller pitch.

22. A fluid pressure mechanism for controlling the rate of pitch change in a variable pitch aircraft propeller, comprising reversible acting pitch changing fluid pressure motors, a regulator rotatable with the propeller and including a fluid pressure source, a governor valve unit carried by the regulator and having a pair of control ports for distributing the fluid pressure to either side of the pitch changing motors in response to change in speed of regulator rotation for maintaining a substantially constant propeller speed, means in said unit for delaying the distribution to said control ports and means for limiting the rate of fluid flow from one of the control ports including a porting sleeve having openings for admission of source pressure and for exit of fluid pressure to the control ports, and a valve plunger slidable in the sleeve having lands adapted to stop flow of pressure fluid to the control ports when the valve is in the on-speed position, with an additional land in close proximity to one of the control port lands adapted to approach the adjacent opening of the sleeve when the plunger moves to said predetermined distributing condition, and restricted openings between the proximate lands brought into action when the valve plunger is in the predetermined distributing condition for reducing the rate of flow of fluid pressure through the associated control port from said fluid pressure motors when the plungertdlilstributes flow tending to decrease propeller p1 c RICHARD E. MOORE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,893,612 Caldwell Jan. '10, 1933 2,028,766 Ernst et al. Jan. 28, 1936 2,163,663 Caldwell June 27, 1939 2,204,639 Woodward June 18, 1940 2,243,852 Caldwell et al. June 3, 1941 2,264,089 Martin Nov. 25, 1941 2,343,382 Martin Mar. 7, 1944 2,364,672 Stevenson Dec. 12, 1944 2,387,896 Giger Oct. 30, 1945 2,391,699 Haines et al. Dec. 25, 1945 2,402,065 Martin June 11, 1946 2,461,791 Warde Feb. 15, 1949 2,467,964 Carson et al. Apr. 19, 1949 FOREIGN PATENTS Number Country Date 501,127 Great Britain Feb. 20, 1939 558,741 Great Britain Jan. 19, 1944

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